Folding rule



May 22, 1928. 1,670,635 I A. F. PLATH FOLDING RULE Filed May 25, 1927 Inventor Patented May 22, 1928..

ARTHUR FRANZ PLATE, F SliOKANE, WASHINGTON.

FOLDING RULE.

Application filed May 25,

My present'invention relates to an improved folding rule of the straight edge type involving the use of an instrument comprising two pivoted straight edges adapted to be adjusted at right angles, and another straight edge, forming the hypotenuse, and arranged to be connected to the two straight edges forming the square portion, at desired distances from the right angles.

The instrument is especially designed for use by carpenters and others, for marking the angle or pitch of a roof on the rafters, or may be used as a protractor, and for various other similar purposes.-

Means are provided for bracing the angular blades when they have been swung on 'their pivot to right-angular position, and means are provided for adjusting the positions of the ends of the angular straight edge forming the hypotenuse blade and re= taining the latter in adjusted position, all as will hereinafter be more fully set forth and claimed.

In the accompanying drawings 1 have illustrated one complete example of the physical embodiment of my invention wherein the parts are combined and arranged according to the best mode I have thus far devised for the practical application of the principles of my invention.

Figure 1 is a perspective view of the instrument in open position for marking the angle or pitch of a rafter.

Figure 2 is a perspective view of the instrument in folded compact position.

Figure 3 is an edge view of the folded instrument.

Figure 4 is an. enlarged sectional detail view at line 4- of Figure 3., and Figure 5 is an enlarged sectional detail view at line 55 of Figure 1.

In carrying out my invention I utilize a base blade 1 and a perpendicular blade 2 fashioned of suitable material and pivoted together at 3, and each of these blades is marked or graduated in inches and fractions thereof similar to the usual foot ruler. The base and perpendicular blades are designed to be retained in position at right angles to one another, and after being swung to this 90 position they are retained therein by means of a diagonal brace comprising two sections 4 and 5, the former pivoted at 6 to the base blade, and the latter pivoted at 7 to the perpendicular blade, and the ends of 1927. Serial No. 194,057.

these sections are provided with a snap-pivot joint 8. Thus when the base blade and perpendicular blade areswung to the 90 angle the two sections of the brace are swung on their pivots to extended position and then snapped at their pivot joint 8 to retain the blades 1 and 2 at right angles.

The blade 2 has an undercut, longitudinally extending groove 9 in one of its sides to accommodate a slide nut 10 and the nut is fashioned with wings 11 to retain it in the groove.

A clamp screw 12 is provided for this nut, and it will beapparent that by turning the screw tight against the face of the grooved blade or against the face of the blade-section 13, the nut is clamped in rigid position, as

will be described.

The angle-blade of which the section 13 forms a part has a hinge or pivot 14 between the blade-section 13 and the section 15, and the latter section is pivoted at 17 on a slide head 18. This slide head is fashioned with a flange 18 movable in an undercut groove 19 extending longitudinally in the face of the base blade 1, and a clamp screw 20 isv used to clamp the head to the base blade.

Thus the two blades 1 and 2 may be swung open on their pivot 8 to perpendicular position and braced by the snap brace-45, then. for marking a rafter, the sectional hypotenuse-blade is opened on its pivot 14.- and the slide head 17 is clamped in adjusted posi tion near the free end of the base blade 1. The slide nut 10 is now moved toward the outer end of the perpendicular blade 2 to a point corresponding to the rise, after which the free end of the hypotenuse-blade, or its f section 13, is brought to rest on the slide 10 and there secured by the thumb screw or clamp screw 12 to give the proper pitch. The outer straight edge of the hypotenuse blade is'now used as a ruler for marking the rafter, or other object to be marked. The same result may be attained by placing the screw head at 20' to line with the twelve inch mark on the blade 1, and then setting the slide stop or nut 10 to the desired mark on the perpendicular blade 2, and other adjustments and rulings may be secured as desired.

Having thus fully described my invention what I claim as new and desire to secure by.

Letters Patent is The combination of a base blade and a Vertical blade pivotally connected to said base blade; each of said blades having an undercut groove, a diagonally arranged seetional brace for said blades, a pivotally connected head slidable in the grooved base blade, a nut slidabl in the grooved Vertical blade and clamp screws for said head and nut, and a foldable hypotenuse blade pivoted to said head and adapted at its free end to be clamped in adjusted position by the 10 nut and screw.

In testimony whereof I aflix my signature.

ARTHUR FRANZ PLATH. 

